Viral Marketing

The Viral Marketing concept is the gold medalist when we talk about using our own clients to spread our company image. Till today there were various techniques to achieve this viral effect but just some of those tehniques have really resulted.
In the following paragraph I will present 6 important aspects of a viral campaign (taken from http://www.wilsonweb.com/wmt5/viral-principles.htm).
An effective viral marketing strategy:

1. Gives away products or services
2. Provides for effortless transfer to others
3. Scales easily from small to very large
4. Exploits common motivations and behaviors
5. Utilizes existing communication networks
6. Takes advantage of others' resources

If you want more information, just go to Wikipedia or Google and take a look on viral marketing and viral advertising resources.